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Question
Two soap bubbles have radii in the ratio 4:3. What is the ratio of work done to blow these bubbles?
Solution
Given: r1 : r2 = 4 : 3
To find: W1 : W2
Formulae: W = 2TdA [½]
Calculation: From formula,
Work done to blow both bubbles,
`W_1-2T(4pir_1^2); and W_2=2T(4pir_2^2)`
`W_1/W_2=(r_1/r_2)^2`
`=(4/3)^2`
=16 : 9
The ratio of work done to blow the bubbles is 16 : 9.
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